Repair Window Sill Concrete

Fix any small or medium cracks in your concrete window sill with caulk.

Repair window sill concrete.

Spread and flatten the caulk with a small putty knife. If the sill is plain concrete it will not need to be painted. Finishing the mortar joint. Repairing window sills isn t a hard diy and i try to share simple ways to make diy improvements to your home.

Keep the sill in one piece so you can use it as a model when cutting the new sill. Scrape away any mess with the edge of the knife. Run a bead of waterproof marine grade adhesive along the old sill. Using a small putty knife starting at the window smooth the caulking flush to the sill.

Use a utility knife and if necessary a hammer to carefully break and remove any caulking or sealant that s binding the old sill to the window frame. Repairing a concrete window sill could appear to be a major job that s far beyond the skills of the average diyer but with the proper knowledge tools material and preparation you might find it s worth considering having a go yourself unless a complete rebuild is necessary. Drill pilot holes every 16 inches or so through the new sill s front and back edges. Gray would look modern.

However you should be able to purchase grey exterior filler which will be a close match to the concrete. You may also need to pry away trim material known as side casing. Fit the narrow tip of a bottle of silicone latex caulk into each crack and overfill it by about inch. Trim the back edge of the new sill as needed so that its lower edge fits tightly against the siding and its back edge fits against the old wood.

If the sill is painted repaint the whole sill as this will give an overall better finish. A window sill is the bottom portion of the window and usually but not always has a lip that overhangs the trim molding and over time these can get damaged or even rot. Use cement or waterproof construction glue to attach the gutter to the window ledge then paint the gutter to match the other ledges or paint them all a different matching color to update the house. Remove the excess material build up on the putty knife.

Fill the crack with multi purpose exterior filler. Use the crow bar or chisel to slowly pry the windowsill off the window.